1. Field of the Invention.
The invention in general relates to line leak test probes which are used in leak detectors which monitor liquid storage and dispensing systems for leaks and more particularly to such a probe which is capable of determining whether or not the pump which pressurizes the system is running and of using this information in optimizing the leak testing procedure.
2. Description of the Prior Art.
Line leak test probes have been used in the petroleum industry for many years. Such line leak test probes generally report to a central monitor which utilizes the leak information to provide warning of leaks and to shut down pumps on lines that are leaking. Such probes have become an essential part of hydrocarbon storage and dispensing facilities since even very small leaks can result in the loss of thousands of dollars in hydrocarbons and the additional expenses of cleanup can be enormous. It is believed that the state of the art of such probes is described in U.S. Pat. No. 4,835,717 issued to Hilary Michel and Laurence S. Slocum which is hereby incorporated by reference. This patent discloses a line leak test probe that includes a microprocessor that is able to distinguish clear cut pressure drops such as those caused by a person opening the dispensing valve before the pump is turned on. However it does not disclose how to distiguish more complicated situations such as the running of the pump and the dispensing of the liquid. Since the running of the pump and the dispensing of the liquid create many large pressure fluctuations and noise, the leak test probe described in the above patent, and all other prior art leak test probes are limited in their ability to detect leaks.